In the case of medical diagnosis of the locomotor apparatus, in particular of one or more joints, it is known to record series of image data records which show the examined joint in a number of positions along one or more motions. The different stages of the motion can then for example be examined with respect to anomalous touches, e.g. a bone scraping against the cartilage, or with respect to the loads and tensions which occur in the joint.
Such joint information relating to motions of the joint can be of a versatile nature. In addition to the physical conditions in the joint itself—i.e. force distributions, tension distributions, touches or irregularities in the motion—the effects on the surrounding tissue, e.g. pressure being exerted on a nerve, can also be examined using the image data records.
In order to obtain a complete set of image data records for a motion, the greatest possible freedom of movement for the patient is required in the receptacle area of the corresponding imaging device. However, this is problematic in many types of imaging devices, particularly in magnetic resonance scanners. There the patient receptacle is usually a relatively narrow tube, for example having a diameter of 60 or 70 cm, in which it is usually only possible to actually record a very small section of such a motion as a result of the cramped spatial conditions. In order to solve this problem, the use of horseshoe-shaped magnets was proposed; however, such systems are more complicated, more expensive and generally do not supply the desired image quality.